1. Field of the Invention
The present invention relates to an imaging apparatus, and in particular, to an imaging apparatus and an imaging system provided with an autofocus function, a control method of the same, and a program which executes the method on a computer.
2. Description of the Related Art
In recent years, imaging apparatuses, such as digital still cameras or digital video cameras (for example, a recorder integrated with a camera) which image a subject such as a person or an animal, generate image data (imaging images), and record the image data as image content, have become widespread. In addition, imaging apparatuses provided with an autofocus function where the focus is automatically adjusted are widespread.
As an imaging apparatus provided with an autofocus function, for example, there is an imaging apparatus which arranges a plurality of ranging areas in the generated imaging image and selects an optimal ranging area out of each of the ranging areas. The function which selects an optimal ranging area in this manner (ranging area selection function) is referred to as, for example, “multi AF”, “multipoint ranging AF”, and “wide AF”.
By performing an imaging operation using the imaging apparatus which is provided with the ranging area selection function, it is possible to adjust the focus to a main subject even in a case where, for example, the main subject is not in the center of the imaging image. That is, since it is possible to adjust the focus to the main subject without any particular operation by a photographer, it is possible for even a beginner to record a suitable imaging image.
Here, in a case where an imaging image is generated using an imaging apparatus, the degree of MTF degradation with regard to a change in image height is different due to individual differences in lenses used in the generation. That is, MTF characteristics are different due to individual differences in lenses used in the generation of the imaging images. As a result, for example, in a case where the imaging image is generated using an imaging apparatus which is able to be mounted with an interchangeable lens, it is important to select the ranging area in consideration of the MTF characteristics of the mounted interchangeable lens.
For example, a camera is proposed which corrects differences in a focus evaluation value due to differences in MTF using a small weighting for ranging areas with a high MTF and a large weighting for ranging areas with a low MTF with regard to the focus evaluation values of the plurality of ranging areas (for example, Japanese Unexamined Patent Application Publication No. 2003-107332 (FIG. 1)).